This paper addresses the question of bicycles as an access mode to train stations in exurban areas. The aim is to provide a method to estimate the modal shift potential from car to cycle (regular bike or pedelec) for residents accessing the station. Putting a figure on this potential makes it possible to refine policies for promoting cycle access to stations like sizing the cycle parking infrastructure, and to assess the benefits of bike and ride solutions for users and communities. Focusing on exurban areas where the level of cycling is low, the study describes a prospective approach to assess the modal shift potential from car to cycle under the assumption of favoring cycle access conditions resulting from proactive policies. In order to build scenarios at a suitable scale for cycling mobility, several high resolution datasets and mapping tools are integrated to support access mode share modeling within the catchment area of the station. The paper describes the access mode share model and its use for prospective analysis about shift potential from car to cycle, on the basis of contrasting scenarios for cycle access conditions and for changes in station ridership. The various modal shift hypotheses are discussed. The method is applied to Val d'Amboise, a French exurban territory with good quality train services and room for growth for cycle access to the station. The prospective situation under a bicycle-friendly scenario is characterized by similar modal shares for the car and the bicycle as access modes to the station, including a high level of pedelec use. Car parking access control at the station would be a key factor to achieve such a modal shift.